Written by Simon R. Green, the first novel in the Deathstalker series.
Owen Deathstalker, latest member of a proud warrior bloodline, is an idle noble, writing history papers and living the good life. Then the Empress outlaws him. In a heartbeat, Owen is running for his life, avoiding the forces of the empire. With his new 'friends' Hazel d'Ark, Jack Random, Ruby Journey, and the Hadenman Tobias Moon, he must discover some way to restore justice to the Empire. Too bad the Empire doesn't want it.
This book, and the others that follow, seem to operate on one basic principal: Just when you think things can't get bigger, they do. And things are pretty big to start with. Green has put everything in these books. Starships, aliens, evil AIs, psionics, swordfights, elfs (Esper Liberation Front), clones, professional rebels, druggies, cyborgs, wampyrs, the dead, and more. A shining example of space opera.
The Deathstalker Books:
Twilight of the Empire is a prequel of sorts, and there could be a sequel/epiloge, Deathstalker Legends.